We revisited the well known Khosrofian and Garetz inversion algorithm [Appl. Opt.22, 3406-3410 (1983)] that was developed to analyze data obtained by the application of the traveling knife-edge technique. We have analyzed the approximated fitting function that was used for adjusting their experimental data and have found that it is not optimized to work with a full range of the experimentally-measured data. We have numerically calculated a new set of coefficients, which makes the approximated function suitable for a full experimental range, considerably improving the accuracy of the measurement of a radius of a focused Gaussian laser beam.
Based on a model introduced by Shen et al. for cw laser induced mode-mismatched dual-beam thermal lens spectrometry (TLS), we explore the parameters related with the geometry of the laser beams and the experimental apparatus that influence the amplitude and time evolution of the transient thermal lens (TL) signal. By keeping the sample cell at the minimum waist of the excitation beam, our results show that high amplitude TL signals, very close to the optimized value, combined with short transient times may be obtained by reducing the curvature radius of the probe beam and the distance between the sample cell and the detector. We also derive an expression for the thermal diffusivity which is independent of the excitation laser beam waist, considerably improving the accuracy of the measurements. The sample used in the experiments was oleic acid, which is present in most of the vegetable oils and is very transparent in the visible spectral range.
Aims: to test the hypothesis that a semi-supervised home physical exercise program improves the functional mobility and quality of life (QOL) of elderly in the community. Methods: This trial was conducted with elderly people (88% female), aged 60 years or older, sedentary and without cognitive decline. Elderly were randomly assigned to an intervention group -IG (home physical exercise and sleep hygiene) and a control group -CG (sleep hygiene). Were applied the International Questionnaire on Physical Activity; mental state mini-exam and the Timed Up and Go test (TUG) before and after the 12-week intervention period. Results: The IG showed an improvement in functional mobility, with a mean reduction in TUG execution time (p <0.01) and improvement in the QOL, (p <0.01) in WHOQOL-OLD. Conclusion: Semi-supervised physical home exercise is effective in improving the functional mobility and the QOL of sedentary elderly in the community. Trial Registration: Registro Brasileiro de Ensaios Clínicos (REBEC)
Nossa sociedade vive em constantes processos de evolução, desta forma mudanças no cotidiano da mesma são proporcionadas pelos avanços tecnológicos. Por conseguinte, em se tratando do contexto educacional, essa evolução deve estar presente na prática educativa e o professor é o grande responsável pela inserção dessa nova realidade na escola. Logo, se os professores e alunos estão inseridos em um universo dinâmico em constante evolução, em contato com tecnologias cada vez mais avançadas, por que não introduzi-las dentro do contexto educacional? A realização de experimentos durante as aulas possui um papel importante para o ensino de Física, pois a preparação para o mundo do trabalho, das ciências e das tecnologias, em especial em uma aula de Física com atividades experimentais apresenta resultados significativos em relação ao aprendizado. Porém, os materiais utilizados no laboratório convencional nem sempre estão facilmente disponíveis em decorrência de um custo muito elevado, são de difíceis acesso e manipulação dentro da realidade de cada escola. Por conseguinte, a criação de experimentos virtuais torna-se uma alternativa para o professor vencer esses desafios. O computador já é um fator motivador para o aluno, que segundo Gaspar (2014), de acordo com a teoria de Vygotsky, para aprender é necessário pensar e para pensar a respeito de um problema o aluno necessita de estímulos. Assim, o presente estudo tem como suporte os resultados de uma pesquisa-ação quali-quantitativa, realizada após a aplicação do produto, com contribuições diversas que visam facilitar o processo de ensino-aprendizagem de Física da teoria à prática.
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